Hi
I doubt BT are worried about this scenario, for a start no one can prove anything as you can't swap out from an ECI cab to an Huawei to prove what speed you would get. Plus VDSL has many variables nothing is guaranteed.
BT never advertised G.INP or that customers speeds might improve because of it and latency may drop (due to the removal of interleaving), and the vast majority of people have no idea about it. Inequality of services exist all over the place even when people are paying more for that service, for example some people commute to work in quiet air conditioned trains with room to sit down whilst others travel in over-crowed dirty carriages with delays and cancellations the norm.
BT are not going to be worried about trying to fix G.INP on ECI cabs as Long Reach G.FAST is what they are trying to get working now, another system hacked about with to satisfy the accountants which will see those with slow VDSL due to line distance stuck on slow VDSL still. Long range G.FAST is struggling to support vectoring where 96 ports are now required rather than G.FASTs design target of 12-16 ports in a pod near to customer premises, so I suspect there will be similar issues where version 2 kit ends up working better than older kit and BT will not bother to fix that either.
Regards
Phil